Which description most clearly defines tone in literature?

Hello, 
the options:
he opinions the writer expresses through characters and events
the way the author conveys themes to the audience through words
the writer’s attitude toward the audience and the subject
the emotional atmosphere created within a work of literature

the way the author conveys themes to the audience through words" is the best option from the list, but it should be noted that there are many other components as well. 
Hope that this would help you! =)